/**
  * Add extra amount which should be taxable by regular tax
  *
  * @param   Mage_Sales_Model_Quote_Item_Abstract $item
  * @param   float $value
  * @param   float $baseValue
  * @param   float $rowValue
  * @param   float $baseRowValue
  * @return  Mage_Weee_Model_Total_Quote_Weee
  */
 protected function _processTaxSettings($item, $value, $baseValue, $rowValue, $baseRowValue)
 {
     if ($rowValue) {
         $this->_isTaxAffected = true;
         $item->unsRowTotalInclTax()->unsBaseRowTotalInclTax()->unsPriceInclTax()->unsBasePriceInclTax();
     }
     if ($this->_helper->isTaxable($this->_store) && !$this->_helper->isTaxIncluded($this->_store) && $rowValue) {
         if (!$this->_helper->includeInSubtotal($this->_store)) {
             $item->setExtraTaxableAmount($value)->setBaseExtraTaxableAmount($baseValue)->setExtraRowTaxableAmount($rowValue)->setBaseExtraRowTaxableAmount($baseRowValue);
         }
     }
     return $this;
 }
 /**
  * Calculate the Weee tax based on the discount and rate
  *
  * @param float $rate
  * @param Mage_Sales_Model_Quote_Item_Abstract $item
  * @param float $discountAmount
  * @param float $weeeAmountIncludingTax
  * @param float $weeeAmountExclTax
  * @return mixed
  */
 private function _getWeeeTax($rate, $item, $discountAmount, $weeeAmountIncludingTax, $weeeAmountExclTax)
 {
     $isWeeeTaxAlreadyIncluded = $this->_weeeHelper->isTaxIncluded($this->_store);
     if ($rate == $this->_calculator->getStoreRateForItem($item) && $isWeeeTaxAlreadyIncluded) {
         if (!$discountAmount || $discountAmount <= 0) {
             //We want to skip the re calculation and return the difference
             return max($weeeAmountIncludingTax - $weeeAmountExclTax, 0);
         } else {
             return $this->_calculator->calcTaxAmount($weeeAmountIncludingTax - $discountAmount, $rate, true, true);
         }
     }
     $discountAmount = !$discountAmount ? 0 : $discountAmount;
     ///Regular case where weee does not have the tax and we want to calculate the tax
     return $this->_calculator->calcTaxAmount($weeeAmountExclTax - $discountAmount, $rate, false, true);
 }